Boffins have discovered the first animal to have sex was a 385 million-year-old Scottish fish called DICKI.

Scientists in Australia claim that fossils show the ancient armoured fish was the first known animal to engage in sexual intercourse.

A study of fossils showed that to transfer sperm, males had grooved L-shaped claspers which were held in place by small paired bones on the female.

The fish, full name Microbrachius dicki, was a three inch-long plcoderm that frolicked in Scottish lakes millions of years before fins evolved into legs.

The findings are thought to be the earliest known example of sexual organs .

(Image: Dr Brian Choo/Flinders University/PA Wire)

Lead scientist Professor John Long, from Flinders University in Adelaide, Australia, said: "Microbrachius means little arms but scientists have been baffled for centuries by what these bony paired arms were actually there for.

"We've solved this great mystery because they were there for mating, so that the male could position his claspers into the female genital area."

Although heralding the finding, researchers said the act of intercourse would look very different – as the fish “did it” sideways, like a square dance.

Prof Long said: “With their arms interlocked, these fish looked more like they are square dancing the do-se-do rather than mating.”

(Image: Roger Jones/PA Wire)

The new discovery implies that external fertilisation evolved from internal fertilisation involving sexual intercourse, and not the other way around.

Scientists said the findings highlights the importance of placoderms in vertebrate evolution.

Prof Long said: “Placoderms were once thought to be a dead-end group with no live relatives, but recent studies show that our own evolution is deeply rooted in placoderms, and that many of the features we have, such as jaws, teeth and paired limbs, first originated with this group of fishes.

“Now, we reveal they gave us the intimate act of sexual intercourse as well.”